Thousands of buoys are employed as aids to navigation, serving, among other things, to indicate channel locations, warn of hazards to navigation, and announce speed or wake restrictions. Navigation buoys are constantly exposed to harsh environmental forces and occasional collisions from watercraft. Sturdy buoy construction and design is required. Additionally, to facilitate the visibility and/or operability of many buoys it is desired that the buoys have a relatively high height above the waterline while demonstrating minimal pitching and rolling during heavy seas, thus requiring the inertia of a heavy overall weight combined with substantial buoyancy and ballasting that achieves a low center of gravity.
To satisfy these requirements, navigation buoys are usually constructed of heavy gauge steel for durability and ballasted with solid ballast at a location below the waterline. Concrete is a commonly used ballast material. Buoys designed to fulfill these requirements are thus very heavy and difficult to handle.
Because of the substantial weight of navigation buoys, buoy retrieval and deployment typically requires relatively large ships with high capacity davits and other specialized equipment (buoy tenders). Even with such equipment, handling heavy buoys can be difficult and dangerous, particularly when high winds and seas complicate retrieval and deployment operations. The capacity of buoy tenders to store buoys once onboard may also be restricted by the heavy weight of the buoys. The stability and trim of buoy tenders may be adversely impacted if too many buoys are stored on deck.
Accordingly, it can be seen that there is a need for a lightweight navigation buoy to facilitate in the buoy's transportation, launching, and retrieval when not deployed that can be altered to exhibit the stability characteristics of the much heavier-constructed conventional buoys when deployed.